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Train Handling During Low Adhesion (rain, Snow, Leaf Fall Etc...)

Discussion in 'Feature Suggestions & Proposals' started by Olaf the Snowman, Feb 2, 2020.

  1. Olaf the Snowman

    Olaf the Snowman Member

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    Inspired by the thread about electric sparks in the winter. Whilst that was about aesthetics and I support the idea, I have an idea about practical handling (as well as aesthetics) of the train and feel this is important because it physically affects the way the train handles depending on conditions thus adapting the way you have to brake/accelerate, etc....


    A brief introduction: in TSW, no matter the weather conditions, the train always accelerates and brakes in the same manner which is not like reality at all. In the real world, there is something call wheelslip when accelerating and wheelslide when braking especially when it has been raining, snowing, leaf fall, etc...


    Ever notice on the Class 377 cab that it has a sticker next to the window about what to do in low adhesion? Well if TSW implements this idea, you can actually follow those instructions instead of it being meaningless because currently the train accelerates perfects and the same in all conditions. See the pictures at the bottom.



    I started wondering off topic/getting very technical so I’m going to include the summary first.

    Summary of the idea:
    1. Aesthetic: Train juddering during wheelslip and wheelslide as well as noises from traction motors/wheels
    2. Aesthetic/function: the sander light working automatically and coming on when sand is being deployed during WSP activity as well as being able to manually deploy sand. Possibly even the speedometer behaving erratically.
    3. Function: physically make acceleration difficult and slower forcing players to reduce power, etc...
    4. Function: physically increase brake distances in low adhesion forcing players (if you haven’t done so already!) to brake earlier and lighter
    I also go into other sorts of weird and wonderful technicalities such as regenerative/rheostatic braking, brake cylinder gauges, TMS, doing RBTs, professional driving policies, etc... but this is FYI only.

    If you’re interested, read ahead to fully understand how low adhesion conditions can significantly alter train’s behaviour (including stuff I wouldn’t expect TSW to actually implement) and how drivers should adapt.


    Wheelslip during acceleration

    Wheelslip during acceleration causes the following things:

    1. It causes the train to judder
    2. The train accelerates slower than in dry conditions
    3. You hear high frequency sounds from the traction motors as they have to work a lot harder especially when full or high power is selected
    4. Sometimes it can be so bad, that the train can’t even move particularly when on a gradient and when on a locomotive as oppose to a (modern) multiple unit

    Here area few videos of trains experiencing wheelslip. You can clearly see the train struggling to accelerate as well as being able to hear high frequency sounds I mentioned.



    I’ll just attach the links rather than embed them all:




    So as a driver, you would need to adapt and do the following:

    1. Reduce power. (as it says in the class 377 cab sticker which you may or may not have noticed) For example, accelerate in notch 3 instead of notch 4
    2. If it is that severe, you may need to do use the sander button to deploy sand
    Wheelslide during braking

    Next, we come in to the braking which is definitely the far bigger issue in low adhesion conditions. Wheelslide causes the following:

    1. Braking in low adhesion conditions can significantly increase braking distance as wheel slide occurs and grip is lost between the wheels and the rail due to ‘contamination’ on the railhead (e.g. rain, leaf residue, snow, etc...). Braking distance can increase dramatically and it’s not unheard of train physically being unable to stop and sliding through a station or in one case I know of, hitting the buffer stops!* If you have experienced extremely bad conditions that you don’t think you will stop, you need to put the emergency brakes on and then report it to the signaller using the ‘Urgent’ call function (yellow button in GSMR radio) and say that you have experienced “reportable” railhead conditions.
    2. Wheel slide protection (WSP) and Auto-sanders on modern trains will automatically detect wheelslide and deploy sand accordingly- this is why in real life, it is not uncommon for the sander light to keep flashing on or off or even remain on continuously during low adhesion so it would be cool to see the sander light actually work in the class 377. In severe wheelslide, the speedometer can act up and you see the needle just jumping up and down. Wheelslide will also cause the train to judder as the WSP will automatically control braking in each vehicle to counteract wheelslide.
    3. If you want to start getting technical, excess wheelslide may cause the train to revert to pure friction braking and so dynamic (rheostatic/regenerative) braking will be lost. On a Class 377, you would know you’ve lost dynamic braking because the brake cylinder gauge (friction braking) would increase in pressure to compensate for the loss of dynamic braking; for example, it may go from 1 bar to 1.5 bar even though you are in the same brake step.

    *For anyone that’s interested, it is the Class 221 that smashed into the buffer stops at Chester. Since the accident, Class 221 now have automatic sanders as I described in point 2. Before they only had one-shot manual sander. (See picture at bottom)



    So as a driver, you would need to do the following:

    1. Brake earlier to ensure you can physically stop at stations and at red signals. For example, hit a station platform at 20mph instead of 30mph. For red signals, when going over the AWS magnet, do no more than 10mph in low adhesion (20mph in normal conditions).
    2. Brake using a lighter step (if possible) to avoid the wheels locking up. I stress, the ‘if possible’ part because if you are worried you are not going to stop, you must not ‘fan’ the brake- increase brake step if you need to or select emergency if you think you won’t make it.
    3. Depending on the traction, you may be required to select a minimum step which ensures (some) friction braking and the use of WSP (this point doesn’t affect class 377s).
    4. Even though the sanders work automatically, you can still manually press the sander button if you so wish to deploy sand.
    5. In Snow conditions only: regular running brake tests (RBT) need to be carried out. In normal conditions, only one RBT needs to be conducted which is done at the first available opportunity in the journey- the purpose of this is to get a feel for the brakes (or test them haha) as brakes are different depending on unit, weather conditions, length of train, etc... So if I was leaving Brighton, when I get to 25mph, I would select brake step 1 and lose 5mph to get down to 20mph and this would be the running brake test completed. That would be it and no more RBTs for the rest of the journey. However, in snowy conditions, a RBT has to be done every 3-5 minutes, in full service brake application as oppose to normal serviceable braking (I.e. step 3 in class 377) and reduction of 10mph- the purpose of this not only includes testing/getting a feel for the brakes but extends to warming up the brake pads to ensure they don’t freeze up.
    6. In Snow conditions only: A maximum speed is usally imposed such as 100mph and 10mph below other speeds to allow for the extended braking distances. Also, depending on traction, regenerative braking may need to be isolated on the TMS or back wall in order to ensure rheostatic braking takes place (the resistors on the roof will be heated up).
    Apologies if I’ve gone in too much detail and started wondering from the actual proposal! But I hope the above information helps you to appreciate that if TSW implement low adhesion conditions with regard to train handling and aesthetics, it adds a whole new element to the game and there is so much more to think about. For those that are playing the game for a bit of fun, you can experience low adhesion and learn how to react differently to the conditions. And for those of you who want to immerse yourself into the world of train driving, you can try and follow the many rules/regulations I have written about if you so wish to make realistic as possible. Aside, if my post means nothing else, I hope some of you realise and begin to appreciate why in particular the autumn season is described as treacherous conditions by drivers and why you may go to a station and hear the following announcement, “Train delayed due to leaves on the line.”

    If you have any questions you’d would like to ask regarding any of the above, please ask away. Remember, some of the stuff I have said are traction specific but I have tried to focus particularly on modern units such as the Class 377/ East Coastway route. Thanks for reading.


    FF9F2A16-7D5B-4CAC-8EBB-82AE0D509FE8.jpeg 88200E17-4080-40A1-950C-9CE061D26B22.jpeg It is blurry but it reads: “In slippery conditions, pull away in notch one (low rate acceleration) up to 5mph before selecting a higher notch; if slip (spin) is noted and the sanding button illuminates, depress the traction sander button for 5-7 seconds; then allow time for the sand to have an effect; if no change is noted and the sander light is still illuminated, depress the sander button again for 5-7 seconds; avoid applying sand over ‘points or crossings’.”
    BC7B8768-07B3-45B1-B1B8-D3A86A609138.jpeg 59A9FA73-137E-4C66-92D7-B0C08F7E644C.jpeg
     
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